python · kyrias · Jun 3, 2017 · Jun 3, 2017 · Jan 25, 2018 · maxking
diff --git a/Lib/email/generator.py b/Lib/email/generator.py
@@ -186,8 +186,9 @@ def _write(self, msg):
        # If we munged the cte, copy the message again and re-fix the CTE.
        if munge_cte:
            msg = deepcopy(msg)
-            msg.replace_header('content-transfer-encoding', munge_cte[0])
            msg.replace_header('content-type', munge_cte[1])
+            if msg.get('content-transfer-encoding') is not None:
+                msg.replace_header('content-transfer-encoding', munge_cte[0])
        # Write the headers.  First we see if the message object wants to
        # handle that itself.  If not, we'll do it generically.
        meth = getattr(msg, '_write_headers', None)

diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py
@@ -311,6 +311,34 @@ def test_as_string_policy(self):
        g.flatten(msg)
        self.assertEqual(fullrepr, s.getvalue())

+    def test_nonascii_as_string_without_cte(self):
+        m = textwrap.dedent("""\
+            MIME-Version: 1.0
+            Content-Type: multipart/alternative;
+             boundary="----5F0D91A9C8C24D91AF71E1D7F2F7877E"
+
+            ------5F0D91A9C8C24D91AF71E1D7F2F7877E
+            Content-type: text/plain; charset=utf-8
+
+            Test if UTF-8 messages with no Content-Transfer-Encoding set can be as_string'd:
+            Föö bär
+            ------5F0D91A9C8C24D91AF71E1D7F2F7877E--
+
+            """)
+        msg = email.message_from_string(m)
+        msg.as_string()
+
+    def test_nonascii_as_string_without_content_type_and_cte(self):
+        m = textwrap.dedent("""\
+            MIME-Version: 1.0
+
+            Test if UTF-8 messages with no Content-Type nor Content-Transfer-Encoding set can be as_string'd:
+            Föö bär
+
+            """)
+        msg = email.message_from_string(m)
+        msg.as_string()
+
    def test_as_bytes(self):
        msg = self._msgobj('msg_01.txt')
        with openfile('msg_01.txt') as fp:

diff --git a/Misc/NEWS.d/next/Library/2018-01-25-21-17-32.bpo-27321.AoxcPm.rst b/Misc/NEWS.d/next/Library/2018-01-25-21-17-32.bpo-27321.AoxcPm.rst
@@ -0,0 +1,2 @@
+Only replace the munged Content-Type-Encoding header when it actually exists
+while flattening an email.
-Original file line number
+Diff line change
@@ -186,8 +186,9 @@ def _write(self, msg):
             # If we munged the cte, copy the message again and re-fix the CTE.
             if munge_cte:
                 msg = deepcopy(msg)
-                msg.replace_header('content-transfer-encoding', munge_cte[0])
                 msg.replace_header('content-type', munge_cte[1])
+                if msg.get('content-transfer-encoding') is not None:
+                    msg.replace_header('content-transfer-encoding', munge_cte[0])
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            maxking
  

      

      

      


        Jun 6, 2019



      
    

  

  
    
      
          
    
  


        
            
  
      
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      Can you set the header if it doesn't already exists?
See #1977 (comment)
    
  
  



    

        
      
  
  
    
  
  
  
    
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             # Write the headers.  First we see if the message object wants to
             # handle that itself.  If not, we'll do it generically.
             meth = getattr(msg, '_write_headers', None)
-          Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Only replace the munged Content-Type-Encoding header when it actually exists
		while flattening an email.